This is what makes people with so many years of experience so valuable. NetApp had a woman who would source parts from around the world and she had done it for long enough that she knew many (if not all) of the tricks in the book. Often her conversations would start with a new supplier and her requests with explicit constraints would tell them that she knew what she was talking about and that they had better play it straight. So they started out assuming none of the tricks they might use with an inexperienced buyer would work. That experience had tremendous value to the company.